1. Field of the Invention
The present invention relates to a sensor element structure, sensor element array, manufacturing method of the sensor element array, and sensing device, which are used in a chemical sensing device and the like.
2. Description of the Related Art
It is generally known that surface Plasmon is induced on a boundary surface between a micro electrically conductive structure and a dielectric material.
This surface Plasmon is known to have a resonance wavelength in response to the structure and change transmitted light, reflected light, and the like from the electrically conductive structure at the resonance time (surface Plasmon resonance).
This surface Plasmon resonance has the resonance conditions decided by a dielectric constant of the periphery of the micro electrically conductive structure. Consequently, the change in the dielectric constant of the periphery of the electrically conductive structure can be detected as a change in the resonance conditions.
Specifically, a change in the resonance conditions can be detected by allowing a light to irradiate and transmit the electrically conductive structure in contact with the dielectric material and measuring a change in optical spectrum.
The surface Plasmon resonance is extremely sensitive to a change in dielectric constant in the periphery of the electrically conductive structure, and this phenomenon is applied to a bio-sensor and the like, thereby realizing a high sensitive sensing.
Hence, the sensing utilizing this surface Plasmon resonance is expected to have a wide range of applications in the fields of medical treatment as well as food, environment, and the like.
For example, when an antigen-antibody reaction is excited in the surface of a metal structure, the antigen-antibody reaction can be detected by using this surface Plasmon resonance.
For example, Richard P. Van Duyne et al (NANO LETTERS, 2004, Vol. 4, No. 6, 1029-1034) disclose the use of a micro Ag thin film fine grain structure formed on a smooth substrate as an electrically conductive thin film structure.
An antigen concentration is measured from a state in which an antibody alone is attached to this structure surface and a change in optical spectrum in a state in which this antibody is further joined with the antigen.
In addition to the above, it is known that a complex of oxygen and substrate, a complementary base pair formation by DNA-DNA hybridization, and the like can be similarly detected.
By the way, as described above, when a change in the dielectric constant in the periphery of the metal structure is detected as a change in optical spectrum by utilizing the surface Plasmon, the change in optical spectrum was small in the conventional configuration.
Hence, a high sensitive sensing has been difficult, and to enable the high sensitive sensing, the increase of change in optical spectrum has been desired.